Liquid crystal coherent transparent display screen and liquid crystal-laser transparent display system

ABSTRACT

A liquid crystal coherent transparent display screen and a liquid crystal-laser transparent display system are provided. The liquid crystal coherent transparent display screen includes a first substrate, a second substrate, a first electrode layer, a first partial reflector, a first alignment layer, a second electrode layer, a second partial reflector, a second alignment layer, and a liquid crystal layer. The first partial reflector and the second partial reflector form an optical resonant microcavity, to replace the polarizer, the analyzer and the optical filters in conventional technology, thereby improving the light transmittance of liquid crystal transparent display.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims benefit of priority to Chinese patentapplication 202211656478.0, titled “LIQUID CRYSTAL COHERENT TRANSPARENTDISPLAY SCREEN AND LIQUID CRYSTAL-LASER TRANSPARENT DISPLAY SYSTEM”,filed Dec. 22, 2022, with the China National Intellectual PropertyAdministration, which is incorporated herein by reference in itsentirety.

FIELD

The present disclosure relates to the technical field of display, morespecifically, to a liquid crystal coherent transparent display screenand a liquid crystal-laser transparent display system.

BACKGROUND

With the continuous development of science and technology, variousdisplay technologies are widely used in daily life and work, bringinggreat convenience to daily life.

Transparent display technology is used to display an image on atransparent medium, which can fuse displayed content and an applicationscenario, such as a combination of virtual displayed content and thereal application scenario on a glass.

Transparent display based on liquid crystal display is a commontransparent display technology. A liquid crystal transparent displaysystem is mainly formed by a broad-spectrum lighting source and a liquidcrystal transparent display screen. A basic display principle thereof isthat polarized light is generated by passing non-polarizedbroad-spectrum light through a polarizer, a liquid crystal state and apolarized state of the light are modified through an electric field, andbrightness modulation and contrast display are achieved by an analyzerorthogonal to the polarizer. In addition, in order to generate colorimage information, the broad-spectrum light is filtered to generatethree primary colors of red, green and blue, and thus the liquid crystaltransparent display system further includes optical filters.

The liquid crystal transparent display system according to theconventional technology includes the polarizer, the analyzer and opticalfilters, resulting in low light transmittance during liquid crystaltransparent display, where the transmittance normally ranges from 5% to10%.

SUMMARY

In view of this, in order to solve the above problems, a liquid crystalcoherent transparent display screen and a liquid crystal-lasertransparent display system are provided according to the presentdisclosure. The following technical solutions are provided.

A liquid crystal coherent transparent display screen is provided, whichincludes: a first substrate, a second substrate, where the secondsubstrate is arranged opposite to the first substrate, a first electrodelayer, arranged on a side of the first substrate facing the secondsubstrate, a first partial reflector, arranged on a side of the firstelectrode layer facing the second substrate, a first alignment layer,arranged on a side of the first partial reflector facing the secondsubstrate, a second electrode layer, arranged on a side of the secondsubstrate facing the first substrate, a second partial reflector,arranged on a side of the second electrode layer facing the firstsubstrate, a second alignment layer, arranged on a side of the secondpartial reflector facing the first substrate, and a liquid crystallayer, arranged between the first alignment layer and the secondalignment layer.

In an embodiment, in the liquid crystal coherent transparent displayscreen, the first substrate is a glass substrate, and the secondsubstrate is a glass substrate.

In an embodiment, in the liquid crystal coherent transparent displayscreen, the first electrode layer is made of indium tin oxide, and thesecond electrode layer is made of indium tin oxide.

In an embodiment, in the liquid crystal coherent transparent displayscreen, the first alignment layer is made of polyimide, and the secondalignment layer is made of polyimide.

In an embodiment, in the liquid crystal coherent transparent displayscreen, the first partial reflector is a high refractive index film, andthe second partial reflector is a high refractive index film.

A liquid crystal-laser transparent display system is provided accordingto the present disclosure, which includes a light source, an opticalmodule and the liquid crystal coherent transparent display screendescribed above.

In an embodiment, in the liquid crystal-laser transparent displaysystem, the optical module includes an optical homogenizer. The opticalhomogenizer is configured to perform homogenizing on light emitted bythe light source.

In an embodiment, in the liquid crystal-laser transparent displaysystem, the optical module further includes a beam shaper. The beamshaper is configured to perform shaping on light outputted by theoptical homogenizer.

In an embodiment, in the liquid crystal-laser transparent displaysystem, the optical module further includes an optical lens. The opticallens is configured to transmit light outputted by the beam shaper to theliquid crystal coherent transparent display screen.

In an embodiment, in the liquid crystal-laser transparent displaysystem, the light source is a laser light source.

Compared with the conventional technology, the present disclosure hasthe following beneficial effects.

The liquid crystal coherent transparent display screen according to thepresent disclosure includes a first substrate and a second substratethat are arranged opposite to each other; a first electrode layerarranged on a side of the first substrate facing the second substrate; afirst partial reflector arranged on a side of the first electrode layerfacing the second substrate; a first alignment layer arranged on a sideof the first partial reflector facing the second substrate; a secondelectrode layer, arranged on a side of the second substrate facing thefirst substrate; a second partial reflector, arranged on a side of thesecond electrode layer facing the first substrate; a second alignmentlayer, arranged on a side of the second partial reflector facing thefirst substrate; and a liquid-crystal layer, arranged between the firstalignment layer and the second alignment layer. The polarizer, theanalyzer and the optical filters in the conventional technology arereplaced by an optical resonant microcavity formed by the first partialreflector and the second partial reflector in the liquid crystalcoherent transparent display screen, thereby improving the lighttransmittance of the liquid crystal coherent transparent display screenduring liquid crystal transparent display.

BRIEF DESCRIPTION OF THE DRAWINGS

In order to more clearly illustrate technical solutions in embodimentsof the present disclosure or in the conventional technology, thedrawings to be used in the description of the embodiments or theconventional technology are briefly described below. Apparently, thedrawings in the following description show only some embodiments of thepresent disclosure, and other drawings may be obtained by those skilledin the art from the drawings without any creative work.

FIG. 1 is a schematic structural diagram of a liquid crystal-lasertransparent display system according to an embodiment of the presentdisclosure;

FIG. 2 is a schematic structural diagram of a liquid crystal-lasertransparent display system according to an embodiment of the presentdisclosure;

FIG. 3 is a schematic structural diagram of a liquid crystal-lasertransparent display system according to an embodiment of the presentdisclosure;

FIG. 4 is a schematic structural diagram of a liquid crystal-lasertransparent display system according to an embodiment of the presentdisclosure;

FIG. 5 is a schematic structural diagram of a liquid crystal-lasertransparent display system according to an embodiment of the presentdisclosure;

FIG. 6 is a schematic structural diagram of a liquid crystal-lasertransparent display system according to an embodiment of the presentdisclosure; and

FIG. 7 is a schematic diagram showing a reflection spectrum of a pixelaccording to an embodiment of the present disclosure.

DETAILED DESCRIPTION

The technical solutions in the embodiments of the present disclosure aredescribed clearly and completely in conjunction with the drawings in theembodiments of the present disclosure hereinafter. It is apparent thatthe described embodiments are only some embodiments of the presentdisclosure, rather than all embodiments. All other embodiments obtainedby those skilled in the art based on the embodiments of the presentdisclosure without any creative work fall within the protection scope ofthe present disclosure.

In order to make the above objectives, features and advantages of thepresent disclosure to be clear and easily understood, the presentdisclosure is further described in detail below in conjunction with thedrawings and specific embodiments.

Reference is made to FIG. 1 , which is a schematic structural diagram ofa liquid crystal-laser transparent display system according to anembodiment of the present disclosure. The liquid crystal-lasertransparent display system includes a light source 11, an optical module12 and a liquid crystal coherent transparent display screen 13 describedin the following embodiment.

In the embodiment of the present disclosure, light emitted by the lightsource 11 is transmitted through the optical module 12 to light theliquid crystal coherent transparent display screen 13. The liquidcrystal coherent transparent display screen 13 operates in a reflectionmode. As shown in FIG. 1 , an eye of an observer and an object arerespectively located in the front of and behind the liquid crystalcoherent transparent display screen 13, achieving a transparent liquidcrystal-laser display technology (LC-LDT) without any polarizer oroptical filters. The LC-LDT without any polarizer or optical filters hasan advantage of high transmittance for incoherent natural light.

It should be noted that in the embodiment of the present disclosure, theliquid crystal coherent transparent display screen 13 operates in thereflection mode for example, while the liquid crystal coherenttransparent display screen 13 may alternatively operate in atransmission mode.

Reference is made to FIG. 2 , which is a schematic structural diagram ofa liquid crystal-laser transparent display system according to anembodiment of the present disclosure.

The light source 11 is a laser light source 14.

In the embodiment of the present disclosure, the laser light source 14serves as a lighting source of the liquid crystal-laser transparentdisplay system. The laser light source 14 has advantages such as goodmonochromaticity and extremely pure color, so that a display image has alarge color gamut. In addition, laser emitted by the laser light source14 has good directionality, which can achieve higher light utilizationefficiency and a high brightness of the display image.

Reference is made to FIG. 3 , which is a schematic structural diagram ofa liquid crystal-laser transparent display system according to anembodiment of the present disclosure.

The optical module 12 includes an optical homogenizer 15.

The optical homogenizer 15 is configured to perform homogenizing onlight emitted by the light source 11.

Reference is made to FIG. 4 , which is a schematic structural diagram ofa liquid crystal-laser transparent display system according to anembodiment of the present disclosure.

The optical module 12 further includes a beam shaper 16.

The beam shaper 16 is configured to perform shaping on light outputtedby the optical homogenizer 15.

Reference is made to FIG. 5 , which is a schematic structural diagram ofa liquid crystal-laser transparent display system according to anembodiment of the present disclosure.

The optical module 12 further includes an optical lens 17.

The optical lens 17 is configured to transmit light outputted by thebeam shaper 16 to the liquid crystal coherent transparent display screen13.

Reference is made to FIG. 6 , which is a schematic structural diagram ofa liquid crystal coherent transparent display screen according to anembodiment of the present disclosure.

The liquid crystal coherent transparent display screen 13 includes afirst substrate 21, a second substrate 22, a first electrode layer 23, afirst partial reflector 24, a first alignment layer 25, a secondelectrode layer 26, a second partial reflector 27, a second alignmentlayer 28, and a liquid crystal layer 29.

The first substrate 21 is arranged opposite to the second substrate 22.

The first electrode layer 23 is arranged on a side of the firstsubstrate 21 facing the second substrate 22.

The first partial reflector 24 is arranged on a side of the firstelectrode layer 23 facing the second substrate 22.

The first alignment layer 25 is arranged on a side of the first partialreflector 24 facing the second substrate 22.

The second electrode layer 26 is arranged on a side of the secondsubstrate 22 facing the first substrate 21.

The second partial reflector 27 is arranged on a side of the secondelectrode layer 26 facing the first substrate 21.

The second alignment layer 28 is arranged on a side of the secondpartial reflector 27 facing the first substrate 21.

The liquid crystal layer 29 is arranged between the first alignmentlayer 25 and the second alignment layer 28.

In the embodiment of the present disclosure, the embodiment isillustrated by taking two pixels as an example. The liquid crystalcoherent transparent display screen 13 has a structure shown in FIG. 6 ,which includes the first substrate 21, the second substrate 22, thefirst electrode layer 23, the first partial reflector 24, the firstalignment layer 25, the second electrode layer 26, the second partialreflector 27, the second alignment layer 28 and the liquid crystal layer29. The first electrode layer 23 and the second electrode layer 26 areconfigured to apply an electric field signal to liquid crystal in theliquid crystal layer 29. The first alignment layer 25 and the secondalignment layer 28 are configured to anchor the liquid crystal in theliquid crystal layer 29.

Further, in the embodiment of the present disclosure, an opticalresonant microcavity is formed by the first partial reflector 24 and thesecond partial reflector 27 in the liquid crystal coherent transparentdisplay screen 13, without the involvement of the polarizer, theanalyzer and the optical filters in conventional technology, therebyimproving the light transmittance during liquid crystal transparentdisplay.

As shown in FIG. 6 , the first electrode layer 23 and the secondelectrode layer 26 apply different voltage signals Von and Voff to apixel at the left and a pixel at the right. Therefore, a liquid crystalstate and an equivalent refractive index of liquid crystal of the pixelat the left are different from a liquid crystal state and an equivalentrefractive index of liquid crystal of the pixel at the right, so thatcorresponding optical resonant microcavities have different equivalentcavity lengths and reflection spectrums.

Further, reference is made to FIG. 7 , which is a schematic diagramshowing a reflection spectrum of a pixel according to an embodiment ofthe present disclosure. FIG. 7 shows a reflection spectrum of the pixelafter a “fully-on” voltage and a “fully-off” voltage are applied to thepixel on the liquid crystal coherent transparent display screen 13, in acase that a laser wavelength is 520 nm.

It should be noted that in FIG. 7 , a refractive index of the liquidcrystal before and after the voltage is applied ranges from 1.58 to1.67, reflectivity of each of the first partial reflector 24 and thesecond partial reflector 27 is 0.15, the liquid-crystal layer 29 has athickness of 1.5 μm, and the laser has an incident angle of 9.2°.

When the “fully-on” voltage is applied to the pixel, a peak of thereflection spectrum of the pixel is overlapped with the laserwavelength, and thus the pixel has a maximum brightness. When the“fully-off” voltage is applied to the pixel, a valley of the reflectionspectrum of the pixel is overlapped with the laser wavelength, and thusthe pixel has a minimum brightness.

It can be seen from the above description that the LC-LDT without anypolarizer or optical filters according to the embodiment of the presentdisclosure fully utilizes a high coherence spectrum feature of the laserlight source, and the reflection spectrum of the optical resonantmicrocavity is changed by modifying the equivalent refractive index ofthe liquid crystal, thereby achieving brightness modification andcontrast display.

In an embodiment of the present disclosure, the first substrate 21 maybe a glass substrate, and the second substrate 22 may be a glasssubstrate.

It should be noted that each of the first substrate 21 and the secondsubstrate 22 may also be made with any other transparent material. Inthe embodiment of the present disclosure, each of the first substrate 21and the second substrate 22 is a glass substrate, for example.

In an embodiment of the present disclosure, the first electrode layer 23may be made of indium tin oxide, and the second electrode layer 26 maybe made of indium tin oxide.

It should be noted that each of the first electrode layer 23 and thesecond electrode layer 26 may also be an electrode layer made of anyother transparent material. In the embodiment of the present disclosure,each of the first electrode layer 23 and the second electrode layer 26is a transparent electrode layer made of indium tin oxide, for example.

In an embodiment of the present disclosure, the first alignment layer 25may be made of polyimide, and the second alignment layer 28 may be madeof polyimide.

It should be noted that each of the first alignment layer 25 and thesecond alignment layer 28 may also be made of any other commonly usedmaterial. In the embodiment of the present disclosure, each of the firstalignment layer 25 and the second alignment layer 28 is made ofpolyimide, for example.

In an embodiment of the present disclosure, the first partial reflector24 may be a high refractive index film, and the second partial reflector27 may be a high refractive index film.

It should be noted that the first partial reflector 24 may be a singlehigh refractive index film, made of, for example, Ta₂O₅, and the secondpartial reflector 27 may be a single high refractive index film, madeof, for example, Ta₂O₅.

In an embodiment of the present disclosure, the liquid crystal in theliquid crystal layer 29 is nematic liquid crystal, for example, 5 CBliquid crystal.

Each of the first partial reflector 24 and the second partial reflector27 may be a single high refractive index film, made of, for example,Ta₂O₅, and reflectivity of the reflector due to a refractive indexdifference between the film and the liquid crystal is low, so that theliquid crystal-laser transparent display system has high transmittancefor incoherent natural light.

Further, the principles of the liquid crystal coherent transparentdisplay screen and the liquid crystal-laser transparent display systemaccording to the embodiments of the present disclosure are furtherdescribed in conjunction with the following specific example.

When laser illuminates the optical resonant microcavity, the laser isreflected and transmitted multiple times on surfaces of the firstpartial reflector 24 and the second partial reflector 27, and multi-beaminterference occurs. In a case that the transmitted light is in phase,constructive interference occurs, which corresponds to a peak of atransmission spectrum of the optical resonant microcavity (that is, avalley of the reflection spectrum). In a case that the transmitted lightis in opposite phase, destructive interference occurs, which correspondsto a valley of the transmission spectrum of the optical resonantmicrocavity (that is, a peak of the reflection spectrum).

Assuming that the equivalent refractive index of the liquid crystal inthe optical resonant microcavity is n, the liquid-crystal layer 29 has athickness of L, and the laser has an incident angle of θ, an opticalpath difference between two adjacent reflected beams is expressed asΔL=2nL cos θ.

In a cast that a phase shift is not considered, a phase difference isexpressed as δ=(4π/λ)nL cos θ.

Assuming that the first partial reflector 24 and the second partialreflector 27 have the same reflectivity R, a transmittance function ofthe optical resonant microcavity is given by the following equation:

${T = {\frac{\left( {1 - R} \right)^{2}}{1 + R^{2} - {2R\cos\theta}} = {\frac{1}{1 + {F{\sin\left( \frac{\delta}{2} \right)}^{2}}}{where}}}},{F = {\frac{4R}{\left( {1 - R} \right)^{2}}.}}$

Without consideration in absorption of light by a medium, thereflectivity of the optical resonant microcavity is expressed as R′=1−T.

When the voltage changes, liquid crystal molecules are rotated to changethe equivalent refractive index n of the liquid crystal, so as to changean equivalent cavity length nL and a spectrum of the reflectivity R′ ofthe optical resonant microcavity.

In a case that a laser spectrum is overlapped with the peak of thereflection spectrum of the optical resonant microcavity, a brightestimage is acquired, and in a case that a laser spectrum is overlappedwith the valley of the reflection spectrum of the optical resonantmicrocavity, a darkest image is acquired. Other voltage signalscorrespond to intermediate brightness states.

The liquid crystal coherent transparent display screen and the liquidcrystal-laser transparent display system according to the presentdisclosure are described in detail above. Specific examples are usedherein to explain the principle and embodiments of the presentdisclosure, and the above description of the embodiments is only used tofacilitate understanding of the method and core concept of the presentdisclosure. Those skilled in the art may make changes to the specificembodiments and the application scope of the present disclosureaccording to the idea of the present disclosure. In view of the above,the content of the specification should not be understood as limitationto the present disclosure.

It should be note that the embodiments in this specification aredescribed in a progressive way, each of the embodiments emphasizes thedifferences from others, and the same or similar parts among theembodiments may be referred to each other. Since the devices disclosedin the embodiment corresponds to the method disclosed in the embodiment,the description of the device is relatively simple, and reference may bemade to the method in the embodiment for the relevant parts.

It should be further noted that the relationship terminologies such asfirst, second or the like are only used herein to distinguish one entityor operation from another entity or operation, rather than tonecessitate or imply that the actual relationship or order existsbetween the entities or operations. Furthermore, terms of “include”,“comprise” or any other variants are intended to be non-exclusive.Therefore, a process, method, article or device including a series ofelements includes not only the elements but also other elements that arenot enumerated, or also includes the elements inherent for the process,method, article or device. Unless expressively limited otherwise, thestatement “comprising (including) one . . . ” does not exclude the casethat other similar elements may exist in the process, method, article ordevice.

Based on the above description of the disclosed embodiments, thoseskilled in the art may implement or carry out the present disclosure. Itis apparent for those skilled in the art to make many modifications tothese embodiments. The general principle defined herein may be appliedto other embodiments without departing from the scope of the presentdisclosure. Therefore, the present disclosure is not limited to theembodiments illustrated herein, but should be defined by the widestscope consistent with the principle and novel features disclosed herein.

The invention claimed is:
 1. A liquid crystal coherent transparentdisplay screen, comprising: a first substrate; a second substrate,wherein the second substrate is arranged opposite to the firstsubstrate; a first electrode layer, arranged on a side of the firstsubstrate facing the second substrate; a first partial reflector,arranged on a side of the first electrode layer facing the secondsubstrate; a first alignment layer, arranged on a side of the firstpartial reflector facing the second substrate; a second electrode layer,arranged on a side of the second substrate facing the first substrate; asecond partial reflector, arranged on a side of the second electrodelayer facing the first substrate; a second alignment layer, arranged ona side of the second partial reflector facing the first substrate; and aliquid crystal layer, arranged between the first alignment layer and thesecond alignment layer.
 2. The liquid crystal coherent transparentdisplay screen according to claim 1, wherein the first substrate is aglass substrate, and the second substrate is a glass substrate.
 3. Theliquid crystal coherent transparent display screen according to claim 1,wherein the first electrode layer is made of indium tin oxide, and thesecond electrode layer is made of indium tin oxide.
 4. The liquidcrystal coherent transparent display screen according to claim 1,wherein the first alignment layer is made of polyimide, and the secondalignment layer is made of polyimide.
 5. The liquid crystal coherenttransparent display screen according to claim 1, wherein the firstpartial reflector is a high refractive index film, and the secondpartial reflector is a high refractive index film.
 6. A liquidcrystal-laser transparent display system, comprising a light source, anoptical module and the liquid crystal coherent transparent displayscreen according to claim
 1. 7. The liquid crystal-laser transparentdisplay system according to claim 6, wherein the optical modulecomprises an optical homogenizer, wherein the optical homogenizer isconfigured to perform homogenizing on light emitted by the light source.8. The liquid crystal-laser transparent display system according toclaim 7, wherein the optical module further comprises a beam shaper,wherein the beam shaper is configured to perform shaping on lightoutputted by the optical homogenizer.
 9. The liquid crystal-lasertransparent display system according to claim 8, wherein the opticalmodule further comprises an optical lens, wherein the optical lens isconfigured to transmit light outputted by the beam shaper to the liquidcrystal coherent transparent display screen.
 10. The liquidcrystal-laser transparent display system according to claim 6, whereinthe light source is a laser light source.